China Launches three Yaogan Satellites to expand Reconnaissance System

September 2, 2013

A Chinese Long March 4C rocket blasted off from the Jiquan Satellite Launch Center at 19:16 UTC on Sunday to deliver a Yaogan Payload to Orbit. The flight was a complete success and delivered a payload of three spacecraft to their target orbit - further expanding China's reconnaissance satellite fleet. The Yaogan Weixing Satellite Fleet consists of remote sensing spacecraft that either carry optical, Synthetic-aperture radar (SAR) or electronic intelligence payloads. According to Chinese Officials, the Yaogan Satellite Constellation is used for scientific experiments, land survey, crop yield assessment, and disaster monitoring. However, it is believed that the satellite system serves military purposes. The real purpose of the satellites is likely to locate and track warships by acquiring their optical signatures and radio transmissions. This launch orbited three Yaogan Satellites, 17A, 17B and 17C. Details on the spacecraft and their respective payloads have not been given. Three Yaogan Spacecraft were also launched by a CZ-4C back in 2009. The Yaogan 9 satellites entered a highly choreographed, triangular constellation in a 1,080 by 1,100-Kilometer Orbit at an inclination of 63.4 degrees - resembling the US NOSS triplets that were used for ELINT purposes until being replaced by duos of NOSS Satellites (Naval Ocean Surveillance System) starting to be launched in 2001. The hypothesis of the Yaogan triplets being similar to the NOSS triplets was firmed up in 2012, when three Yaogan 16 satellites were delivered to orbit and entered formation in a second orbital plane west of that of Yaogan 9. The Yaogan 17 launch entered an orbital plane about 75 degrees east of Yaogan 9 - creating an operational system that closely resembles the pattern of NOSS satellites launched in 2007, 2011 and 2012 that show a 74-degree spacing in planes. US Space Surveillance tracked the three Yaogan 17 spacecraft in a 1,079 by 1,108-Kilometer orbit at an inclination of 63.4 degrees.

The Long march 4C Launch Vehicle is part of China's flight proven Long March Rocket family. It is derived from the CZ-4B Launcher, but features a re-startable upper stage and can accommodate a larger Payload Fairing. It is operated from the Jiquan and Taiyuan Satellite Launch Centers. CZ-4C has a liftoff mass of 250,000 Kilograms and is 45.8 meters in length with a diameter of 3.35 meters. It features several improvements over the CZ-4B such as new telemetry, tracking, control, and self-destruction systems that are smaller in size. The first stage of the vehicle is powered by a YF-21B Rocket Engine which consists of a cluster of four YF-20B Engines each providing 814 Kilonewtons of Vacuum Thrust. At liftoff, the YF-21B provides a thrust of 2,962 Kilonewtons generating a total Thrust-to-Weight ratio of 1.21. The Engine Assembly has a weight of 2,850 Kilograms, is 3.3 meters in length and 3.5 meters in diameter.

Photo: China Ministry of Defense

Photo: China Ministry of Defense

The engine nozzles are gimbaled for vehicle control. All three Stages of the vehicle use Nitrogen Tetroxide as oxidizer and Unsymmetrical Dimethylhydrazine as fuel. The first stage has a liftoff mass of 193,300 Kilograms including 183,300 Kilograms of propellants. It is 24.7 meters in length. The second stage of the vehicle is powered by a YF-22B Main Engine providing 738 Kilonewtons of thrust and a four-chamber vernier yet designated YF-23F providing 46 Kilonewtons of thrust. The main engines is fixed while the four vernier nozzles can be gimbaled for attitude control during powered flight. The stage is 10.4 meters long and holds 35,370 Kilograms of storable propellants. Both, the first and second stage, are based on components that are flown on other CZ Rockets. The third stage however, is a specially designed rocket stage for the Long March 4C and its purposes.

The stage is 4.9 meters long and has a reduced diameter of 2.9 meters. Liftoff mass is 14,560 Kilograms including 12,800 Kilograms of propellants. It uses a 98-Kilonewton YF-40 Rocket Engine. YF-40 has a dry weight of approximately 166 Kilograms and a diameter of 0.65 meters. It provides re-ignition capability to the vehicle in order to target a variety of orbits and provide precise injection capabilities.

Long March 4C is capable of delivering payloads of up to 4,200 Kilograms to Low Earth Orbit. Sun Synchronous Orbit capability is 2,800 Kilograms and Payloads of up to 1,500 Kilograms can be delivered to Geostationary Transfer Orbit by the Long March 4C.

Chinese officials reported launch success late on Sunday. This was the 180th successful Chinese orbital launch, the 180th successful launch of the Long March launcher family and the 6th Chinese launch to orbit this year.

Jiquan has been particularly busy this year, hosting four of the six orbital launches, including the manned Shenzhou 10 mission. The Jiquan Satellite Launch Center which is also known as Shuang Cheng Tze launch center was China's first launch facility being established in 1958. It is located in the Gobi Desert about 1,600 Kilometers from Beijing. The Center includes a large amount of facilities including two launch complexes, a technical center and a Mission Command and Control Centre/Launch Control Center as well as Ground Support Equipment needed for rocket launches such as propellant systems, tracking assets, weather forecast equipment and logistic support facilities. Initially, Jiquan was used for satellite launches into Low Earth Orbit with high inclinations. Currently, its only active launch site is Launch Area 4 featuring two SLS - South Launch Site - Launch Pads. SLS-1 is used to support the manned space program while the SLS-2 site is used for satellite launches.

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